Re: [PATCH] move the kernel to 16MB for NUMA-Q

[Rene Herman]

On 06/11/2007 07:58 PM, H. Peter Anvin wrote:

> Rene Herman wrote:
> > Aligning the kernel image on 4M could gain an additional TLB entry if
> > the kernel image would fit in one (4M aligned) hugepage, but not in the
> > 3M that's left after loading the kernel at 1M physical. And that stuff
> > about the MTRRs...
>
> Yup.  Most CPUs won't actually use a largepage for the kernel if it's
> below 4 MB (2 MB with PAE, so that's what x86-64 uses.)

Oh, thanks, that's interesting. Had no idea. In those cases it would seem to 
at least potentially be a serious performance issue.

Rene.

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